单项选择题
A.A large FTP job is in process.
B.A network interface was misconfigured.
C.The ping command is being used excessively.
D.A bad network interface card and/or network cable is in use.
单项选择题 Whichofthefollowingreasonsindicatewhyitisimportanttohavetheuserdemonstratethetasktheyaretryingtoperform?（）
单项选择题 Whichofthefollowingcommandsshouldbeusedtoassurethatadumpcanbeforcedusingtheresetbuttononasystemwithoutakeyswitch?（）
单项选择题 WhichofthefollowingcommandsisusedtodeterminetheroutethattheIPpacketstaketoanetworkhost?（）